'We had four years to prepare for these attacks,' says Crispin Black in his damning review of the security and intelligence networks that failed to anticipate the London bombings. 'Can we really maintain that we performed well enough?'

Black, a former government intelligence adviser, is questioning the official assertion that everything which could have been done to prevent the attacks of 7 July had been done. It is a question that certainly needs to be raised - but can our intelligence services really be blamed for failing to detect four British-based men bringing home-made bombs on to London's transport system?

The specific answer is no. Black acknowledges that such a plot was always going to be 'very difficult' to foil. But there is culpability, he argues, on a much wider scale. The relaxation of security a month before the attacks and the shock that followed when the nationality of the bombers was revealed point to something gravely wrong at the heart of Britain's defence.

What Black exposes is an 'antiquated, divided intelligence structure' unequal to modern terrorism. But reform, he fears, will not happen easily. The old ideas are too deep-rooted and those who hold them are simply not prepared to accept the criticism necessary for change.

One such idea is the assumption that by allowing Islamic extremists into Britain, the Muslim populace will be appeased and attacks on home soil prevented. Black warns against equating extremism with 'mainstream' Muslims. He advocates a more hard-line approach and points to the 'tough' French system as a model.

As sensitive as Black is to the delicacies involved in placing the Muslim community under tight surveillance, his prescriptions require further debate. We have only to look at the unrest in Paris to see the downsides of a hard-line approach.

Books produced very rapidly in the wake of major events risk becoming just as rapidly obsolete. But it seems that What Went Wrong? will remain pertinent for quite some time.